On Wed, May 12, 2021 at 6:32 AM Tom Lane <t...@sss.pgh.pa.us> wrote:
>
> Amit Kapila <amit.kapil...@gmail.com> writes:
> > I have closed this open item.
>
> That seems a little premature, considering that the
> contrib/test_decoding/sql/stats.sql test case is still failing regularly.
Thank you for reporting.
Ugh, since by commit 592f00f8de we send slot stats every after
spil/stream it’s possible that we report slot stats that have non-zero
counters for spill_bytes/txns and zeroes for total_bytes/txns. It
seems to me it’s legitimate that the slot stats view shows non-zero
values for spill_bytes/txns and zero values for total_bytes/txns
during decoding a large transaction. So I think we can fix the test
script so that it checks only spill_bytes/txns when checking spilled
transactions.
For the record, during streaming transactions, IIUC this kind of thing
doesn’t happen since we update both total_bytes/txns and
stream_bytes/txns before reporting slot stats.
I've attached a patch to fix it.
Regards,
--
Masahiko Sawada
EDB: https://www.enterprisedb.com/
diff --git a/contrib/test_decoding/expected/stats.out b/contrib/test_decoding/expected/stats.out
index 7d174ee8d2..19bbd76c10 100644
--- a/contrib/test_decoding/expected/stats.out
+++ b/contrib/test_decoding/expected/stats.out
@@ -111,10 +111,10 @@ SELECT wait_for_decode_stats(false, true);
(1 row)
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
- slot_name | spill_txns | spill_count | total_txns | total_bytes
------------------------+------------+-------------+------------+-------------
- regression_slot_stats | t | t | t | t
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
+ slot_name | spill_txns | spill_count
+-----------------------+------------+-------------
+ regression_slot_stats | t | t
(1 row)
-- reset the slot stats, and wait for stats collector to reset
@@ -149,10 +149,10 @@ SELECT wait_for_decode_stats(false, true);
(1 row)
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
- slot_name | spill_txns | spill_count | total_txns | total_bytes
------------------------+------------+-------------+------------+-------------
- regression_slot_stats | t | t | t | t
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
+ slot_name | spill_txns | spill_count
+-----------------------+------------+-------------
+ regression_slot_stats | t | t
(1 row)
-- Ensure stats can be repeatedly accessed using the same stats snapshot. See
diff --git a/contrib/test_decoding/sql/stats.sql b/contrib/test_decoding/sql/stats.sql
index 263568b00c..93b6103034 100644
--- a/contrib/test_decoding/sql/stats.sql
+++ b/contrib/test_decoding/sql/stats.sql
@@ -73,7 +73,7 @@ SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL,
-- exact stats count as that can vary if any background transaction (say by
-- autovacuum) happens in parallel to the main transaction.
SELECT wait_for_decode_stats(false, true);
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
-- reset the slot stats, and wait for stats collector to reset
SELECT pg_stat_reset_replication_slot('regression_slot_stats');
@@ -83,7 +83,7 @@ SELECT slot_name, spill_txns, spill_count, total_txns, total_bytes FROM pg_stat_
-- decode and check stats again.
SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
SELECT wait_for_decode_stats(false, true);
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
-- Ensure stats can be repeatedly accessed using the same stats snapshot. See
-- https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i%40alap3.anarazel.de
